JPH0464154B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a high-frequency heating device that achieves uniform heating distribution.

Conventional technology A high-frequency heating device that heats a dielectric material using high frequency waves generates a standing wave in the heating chamber due to the interaction between the wavelength of the high frequency wave, the heating chamber, and the size and shape of the object to be heated, thereby heating the object. The problem is that non-uniformity occurs. Therefore, in order to make the heating distribution uniform, there is a turntable method in which the object to be heated is heated while rotating it on a turntable, a stirrer method in which metal blades are rotated in the heating chamber and the electromagnetic waves are stirred, and electromagnetic waves are heated. There is a rotating waveguide method that rotates and heats the antenna, which is the radiation source. FIG. 3 shows a conventional high-frequency heating device in which a high-frequency excitation port is provided at the bottom of a heating chamber using a rotating waveguide system. A high frequency wave generated from a high frequency oscillator 1 is transmitted to an excitation port 4 of a heating chamber 3 through a waveguide 2. The high frequency wave transmitted to the excitation port 4 is transmitted to the rotating waveguide 6 by the coaxial antenna 5. The rotating waveguide 6 has an opening 6a at its end in order to emit high frequency waves from a specific direction within the heating chamber 3. A plate pedestal 7 made of a low-loss dielectric material is provided above the rotating waveguide 6 on which an object to be heated is placed, and the rotating waveguide 6 is rotationally driven by a motor 8 . The rotating waveguide 6 has a box shape that covers the excitation port 4, has a gap between it and the bottom wall surface of the heating chamber 3, and is rotatable, and has an opening 6a facing the heating chamber at its end to rotate and radiate high frequency waves.

Problems to be Solved by the Invention The reason why such a configuration for radio wave agitation is adopted is that when heating the object to be heated, the high frequency waves from the excitation port 4 directly reach the center of the bottom of the object to be heated. Most of the high frequency waves from the excitation port 4 are radiated from the opening 6a of the rotating waveguide 6 in order to prevent heating of that part. However, conversely, with such a configuration, there was a problem in that the heating at the center of the bottom surface of the object to be heated was too weak.

The present invention solves the above-mentioned conventional drawbacks and provides a high-frequency heating device with uniform heating distribution.

Means for Solving the Problems The high-frequency heating device of the present invention for solving the above-mentioned problems includes a heating chamber for heating an object to be heated, a high-frequency oscillator for oscillating high-frequency electromagnetic waves, and a high-frequency oscillator installed on the wall of the heating chamber. The rotating waveguide is equipped with an excitation port that supplies the high-frequency electromagnetic waves of the oscillator to the heating chamber, and a rotating waveguide that covers the excitation port and rotates parallel to the heating chamber wall surface around the excitation port and has an opening at the end. has a flat part substantially parallel to the wall surface of the heating chamber where the excitation port is provided,
This structure has an opening in a part of the plane part, and an antenna that is substantially perpendicular to the plane part in this opening part.

Function The high-frequency heating device of the present invention solves the problem of the rotating waveguide by providing an opening near the center of rotation of the rotating waveguide and an antenna that extracts radio waves from the opening. Eliminates the weak heating of the bottom surface of the heated object directly above the center of rotation. Furthermore, by providing the antenna in the opening, the area of the opening can be made much smaller than when only the opening is provided, so that the rotating waveguide does not suffer from insufficient strength.

Embodiment Hereinafter, an embodiment of the present invention will be described based on the drawings.

In FIG. 1, high frequency waves generated from a high frequency oscillator 1 are transmitted through a waveguide 2 to an excitation port 4 opened at the center of the bottom wall of a heating chamber 3. The high frequency wave transmitted to the excitation port 4 is sent to a rotating waveguide 6 by a coaxial antenna 5.
transmitted to. The rotating waveguide 6 has an opening 6 at the end in order to emit high frequency waves from a specific direction within the heating chamber 3.
It has a. A dish pedestal 7 made of a low-loss dielectric material is provided above the rotating waveguide 6 on which an object to be heated is placed. Further, the rotating waveguide 6 is rotationally driven by a motor 8 via the coaxial antenna 5. The rotating waveguide 6 is box-shaped so as to cover the excitation port 4, and has a gap 9 between it and the bottom wall of the heating chamber so as to be rotatable. Rotating and radiating high frequency waves. Further, the upper surface of the rotating waveguide 6 near the center of rotation has an opening 6b, and in order to extract a part of the radio waves from this opening 6b, the opening 6b
An antenna 6c is provided which is integrally cut and raised to form the antenna. Then, from the aperture 6b, the antenna 6
c, radio waves are efficiently extracted and heat the center of the bottom of the object to be heated. Therefore, the high-frequency waves from the high-frequency oscillator 1 are transmitted through the rotating waveguide 6 and emitted from the two openings 6a and 6b of the rotating waveguide 6. radio wave distribution can be obtained. Further, depending on the characteristics of the radio wave distribution in the heating chamber 3, two or more openings and antennas may be provided. However, in order to obtain an effect sufficient to improve the heating distribution of the object to be heated by simply opening the opening, a considerably large opening is required. It is very difficult to provide a large opening at the center of rotation, and even if one were provided, the area of the opening would be large and would result in heating not only the center of the bottom surface of the object to be heated, but the entire bottom surface. Therefore, by combining a relatively small aperture and an antenna as in the present invention, it is possible to radiate radio waves to a weakly heated area in the center of the bottom surface and achieve uniform heating.
Furthermore, even if the high-frequency heating device is reversed during transportation, the antenna 6c portion will hit the dish pedestal 7, and the rotating waveguide 6 can be prevented from coming off from the motor 8 to which it is detachably connected via the coaxial antenna 5.

Effects of the Invention As described above, the high-frequency heating device of the present invention can obtain the following effects by providing an opening and an antenna at the center of rotation of the rotating waveguide.

(1) The shortcoming of heating using a rotating waveguide is the lack of heating at the center of the bottom of the object to be heated, and an ideal high-frequency heating device for the heating area can be realized.

(2) Since the heating chamber is excited by vertical radio waves, stable and uniform heating is possible even if the shape of flat food changes.

(3) Since the opening provided in the rotating waveguide and the antenna part can be realized by cutting and processing sheet metal, mold cost, processing cost, and parts cost are low.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of a high-frequency heating device according to an embodiment of the present invention, FIG. 2 is a perspective view of the rotating waveguide portion of FIG. 1, and FIG. 3 is a vertical cross-sectional view of a conventional high-frequency heating device. It is. DESCRIPTION OF SYMBOLS 1... High frequency oscillator, 2... Waveguide, 3... Heating chamber, 4... Excitation port, 5... Coaxial antenna, 6...
...rotating waveguide, 6a...opening A, 6b...opening B, 6c...antenna, 7...pan pedestal.

Claims (1)

[Scope of Claims] 1. A heating chamber that heats an object to be heated, a high-frequency oscillator that oscillates high-frequency electromagnetic waves, and an excitation port that is provided on a wall of the heating chamber and supplies the high-frequency electromagnetic waves of the high-frequency oscillator to the heating chamber. , a rotating waveguide that covers the excitation port, rotates around the excitation port in parallel to the wall surface of the heating chamber, and has an opening at an end;
The rotating waveguide has a plane part that is substantially parallel to the wall surface of the heating chamber in which the excitation port is provided, and has an opening in a part of the plane part, and the opening part has a plane part that is substantially perpendicular to the plane part. A high-frequency heating device configured with an antenna. 2. The high-frequency heating device according to claim 1, wherein the opening of the flat part of the rotating waveguide and the antenna are formed by cutting and raising the flat part integrally from the flat part.